Motor Symptoms:
There are four motor symptoms which are considered cardinal in Parkinson’s disease.

These four symptoms areTremorRigiditySlowness of movementPostural instability

Tremor:
This symptom is most apparent and well-known in 30% of patient with PD don’t have tremors at disease onset. Most develop it as the disease progresses. It is usually a rest tremor. Maximal when the limb is at rest and disappearing with voluntary movement and sleep.
It affects to a greater extent the most Distal pact of the limb and at the onset typically appears in only a single arm or leg, becoming bilateral later. Frequency of PD tremor is between 4-6 hertz cycles per second. Pill rolling tremor the tendency of the index finger of the and to get into contact with the thumb and perform together a circular movement.

Rigidity:
It is stiffness and resistance to limb movement caused by increased Muscle Tone, excessive and continuous contraction of muscles. Rigidity is uniform (Lead-pipe rigidity) or ratchet (Cogwheel rigidity). The combination f tremor and increased tone is considered to be at the origin of cogwheel rigidity. It may be associated with joint pains, frequent. In the beginning it is asymmetrical rigidity, neck is affected shoulder muscles prior to the muscles of the face and extremities. Rigidity affects the whole body and reduces the ability to move.

Hypokinesia (Slowness of movement):
It is associated with difficulties along the whole course of the movement process, from planning to initiation and finally execution of a movement. Performance of sequential and simultaneous movements is hindered. Bradykinesia is a very disabling symptom in the early stages of the disease. Initial complaints are problems when performing daily tests which require fine motor control like writing, sewing or getting dressed.

Clinical evaluation is based in similar tasks such as alternating movements between both hands or both feet.
Bradykinesia is not equal for all movement or times. It is modified by the action activity or emotional state of the subject, to the point that some people are barely able to walk yet can still ride a bicycle. Generally people with PD have less difficulty when some sort of external cue is provided.

Postural Instability:
It is seen in the last stage of disease, leading to impaired balance and frequent falls, then to bone fractures. Up to 40% may experience falls and around 10% may have falls weekly, with number of falls being related to severity.

Festinating (rapid shuffling steps and forward flexed pasture when walking, speech, swallowing disturbances, including voice disorder may be seen. Mask like face expression or small handwriting may seen.

Parkinsonism word is used for a motor syndrome. The main symptoms are tremor at rest, stiffness, slowing of movement and postural instability.
Parkinsonian syndromes can be divided into four subtypes according to their origin:
1. Primary/Idiopathic
2. Secondary/Acquired
3. Hereditary P
4. Parkinson Plus Syndrome/ Multiple System Degeration

Primary Parkinsonism:
It means Parkinsonism with no external identifiable cause. In recent years several genes that are directly related to some causes of Parkinson’s Disease have been discovered.

The term Familial Parkinson’s Disease and Sporadic Parkinson’s Disease can be used to differentiate genetic from truly idiopathic forms of disease.

Usually classified as a movement disorder PD also gives rise to many non-motor types of symptoms like sensory deficits, cognitive difficulties or sleep problems.

In terms of pathophysiological part, PD is considered a Synucleiopathy due to abnormal accumulation of alpha synuclein protein in the brain in the form of Lewy Bodies, as opposed to other disease such as Alzheimer’s Disease, where the brain accumulates Tan Protein in the form of Neurofibrollary Tangles.

The most typical symptoms of the Alzheimer’s Disease, dementia, occurs in advanced stages of PD, while it is common to find neurofibrillary tungles in brains affected by PD.

Dementia with Lewy Bodies (DLB) is another synucleiop that has similarities with PD, and especially with the subsets of PD cases with dementia.